The term 'Summer Flower' can be broken down into four crossword solutions: ANNUAL (6 letters), Phlox (5 letters), Zinnia (6 letters), and NASTURTIUM (10 letters). Annuals are plants that complete their life cycle in one growing season, while perennials live for more than two years. Phlox is a genus of flowering plants in the family Polemoniaceae, which includes 67 species of annuals, perennials, and subshrubs. Zinnias are popular garden flowers that come in a variety of colors and sizes. Nasturtiums are an edible flower with a peppery flavor, often used as a garnish or in salads.